Having plants indoors is always nice. Having a lovely fresh smell, and a sign of life is actually beneficial in the home. The only downfall is forgetting to water them. Some plants are OK with minimal water, but if you don't like cacti, then your plants might quickly die.
Dr.mcc, an instructables user, has created a little project to display the moisture in the soil of a plant pot. The display isn't just some boring chart though, it's a lovely little emoticon! When the soil gets a bit too dry, the display will show a sad face, and when there is enough moisture the little face will show up happy!
It's a great little project that adds a little human element to a seemingly lifeless and needy plant. If you always forget to water your plants, or fancy getting your kid into maintaining you indoor garden, it's a great project that is pretty cheap to make.
The design is fairly simple, and Arduino Pro Mini and FTDI board, an 8x8 LED matrix and a moisture sensor for the main design, and some nuts, bolts and acrylic sheets for the case. It could be knocked up in a couple of hours, and your plants will never suffer again. You could always add an audible buzzer, or get it to tweet and e-mail you when it's getting dry.
It's a pretty novel way to get you to water your plants - the sad little face will guilt you into it!